Food safety remains a critical issue for human health in our society. The food system in our nation is vulnerable to contamination from natural pathogens and from bio-terrorist attack. Current detection methods are inadequate due to the time-consuming and laboratory-centered approaches presently in use. Instruments for rapid on-site detection of pathogens in food are urgently needed. The objective of this project is to evaluate an innovative capillary bioseparator / bioreactor-based optical biosensor technology for rapid detection of E. coli O157:H7. The detection limit, specificity and detection time possible with this approach will be evaluated. It is expected that the technology will provide <100 cells/ml detection limit, <1 h detection time, and high specificity to E. coli O157:H7 (<1% false positive/negative data). Although the initial work will focus on food safety, similar technology can be utilized for rapid, on-site screening of human E. coli infections. Rapid screening of human infections is also very important because life-threatening E. coli infections are increasing especially in susceptible groups such as premature babies. Preliminary data indicate that the proposed approach has good potential to significantly improve the state-of-the-art in rapid, sensitive, and specific detection of E. coli O157:H7 and eventually other biological pathogens.